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Escape

Escapep

Recognizer for escape structures.

Signature
(escapep x) → *

Definitions and Theorems

Function: escapep

(defun escapep (x)
  (declare (xargs :guard t))
  (let ((__function__ 'escapep))
    (declare (ignorable __function__))
    (and (consp x)
         (cond ((or (atom x) (eq (car x) :single-quote))
                (and (true-listp (cdr x))
                     (eql (len (cdr x)) 0)
                     (b* nil t)))
               ((eq (car x) :double-quote)
                (and (true-listp (cdr x))
                     (eql (len (cdr x)) 0)
                     (b* nil t)))
               ((eq (car x) :backslash)
                (and (true-listp (cdr x))
                     (eql (len (cdr x)) 0)
                     (b* nil t)))
               ((eq (car x) :letter-n)
                (and (true-listp (cdr x))
                     (eql (len (cdr x)) 0)
                     (b* nil t)))
               ((eq (car x) :letter-r)
                (and (true-listp (cdr x))
                     (eql (len (cdr x)) 0)
                     (b* nil t)))
               ((eq (car x) :letter-t)
                (and (true-listp (cdr x))
                     (eql (len (cdr x)) 0)
                     (b* nil t)))
               ((eq (car x) :line-feed)
                (and (true-listp (cdr x))
                     (eql (len (cdr x)) 0)
                     (b* nil t)))
               ((eq (car x) :carriage-return)
                (and (true-listp (cdr x))
                     (eql (len (cdr x)) 0)
                     (b* nil t)))
               ((eq (car x) :x)
                (and (true-listp (cdr x))
                     (eql (len (cdr x)) 1)
                     (b* ((get (std::da-nth 0 (cdr x))))
                       (hex-pairp get))))
               (t (and (eq (car x) :u)
                       (and (true-listp (cdr x))
                            (eql (len (cdr x)) 1))
                       (b* ((get (std::da-nth 0 (cdr x))))
                         (hex-quadp get))))))))

Theorem: consp-when-escapep

(defthm consp-when-escapep
  (implies (escapep x) (consp x))
  :rule-classes :compound-recognizer)